Read Ginerva Liptons book The Fibro Manual. It explains most of this for you. She is an MD with fibro

I honestly feel it weakens your immune system with all the pain and fatigue

Yes. Fibro, per my Dr. Is an autoimmune disease, so our immune system is not working correctly. A lot of the time it can affect you in that way. Also some of a persons illnesses could have been there before and they just had not been found before that person was diagnosed with fibro.

I think it might be due to our immune systems. They don't work. I too have more than just the fibro. I have IBS, migraines, depression, toe nail fungus, herniated discs in my lower back and in my neck. I have cervical pain shoulder arm and hand pain. I have reynauds in my hands and feet.

Fibro and ptsd can cause a range of symptoms including insomnia, irregular heartbeat, chronic headaches, ibs. Liver damage could be from meds...i had to stop taking tylenol. Compromised immune system also makes you prone to rashes. All connected.